1. Field of the Invention
The invention relates generally to the quick engagement of planar workpieces in a steady upright position while work is done upon them and more specifically to the quick engagement and disengagement of a door, window, or plasterboard as such an objects is cut, trimmed, painted or prepared for lock and hinge installation.
2. Description of the Prior Art
There are numerous devices in the field of door holders and clamps dating back to the nineteenth century. These devices can be separated into two basic mechanisms. One type of mechanism uses a brace or a plurality of braces to hold the door or other planar piece on edge and the positioning of the braces is secured by either a wedge (U.S. Pat. No. 7,125,009), a screw (e.g. U.S. Pat. No. 6,886,821), a pin (e.g. U.S. Pat. No. 5,294,099), a retractable spring (e.g. U.S. Pat. No. 4,391,437), or fixed ridges (e.g. U.S. Pat. No. 2,621,687). Another type uses the weight of the workpiece itself in order to actuate stabilizing braces or jaws. U.S. Pat. Nos. 5,513,836, 4,799,658, 4,270,741, 2,971,548 and 2,605,795 all disclose a holding mechanism actuated by the weight of the workpiece.
Although this latter type of mechanism permits automatic clamping, all such devices employing it to date are composed of numerous parts and contain several points of friction between the receiver and the clamping mechanism. There is thus a need in the art for a simple, inexpensive and maintenance free way to quickly secure planar workpieces.